90camaroirocz

I did a fuel pressure check on my 90 iroc 350 tpi it only has 25 psi and i ordered a walbro 255 should be here any day now how much difference you think it going to make and what fuel pressure you think i should run it at all i have right now is an air foil and 3in catback exhuast w/ flowmaster

WhiteKnight

i dont think you're really going to see any gains at the moment. The factory pump should be giving ya enough gas until your engine is more modded.

90camaroirocz

i dont think its giving me enough gas at 25 psi when its supose to be 42psi

firebirdjosh

iTrader: (1)

FP guages are notorious for being innacurate. I doubt it'd run at 25 psi but I'm certainly not an expert. Do you have an adjustable fuel pressure regulator? If not you won't see a difference over stock performance.

90camaroirocz

my craftsman fuel pressure tester im sure is pretty accurate an i dont have adjustable reg i was thinking about getting one about a month ago it was at 30 psi and i have changed fuel filter

ZZ28ZZ

On my TPI, I've adjusted the fuel press down to 20 psi while idling and the eng kept running.

With the correct fuel press, you'll have better accelaration and the eng will run smoother at all speeds due to better fuel atomization.

If you want a AFPR (adj fuel press reg), Holley makes a very nice one.

anthony64ss

iTrader: (1)

Did you unplug the vacuum line to the regulator while you checked for pressure? You are supposed to. Start simple, you said you replaced fuel filter. Thats a good start, next try the regulator diaphram. Fuel pump would be the last thing i replace. A new pump wont make a difference if your regulator is shot. Good luck with your walbro though

DJP87Z28

Checking with a fuel pressure gage, key on engine off FP 36/38 PSI and with the engine running at idle 38/40 PSI. Set at WOT per instuctions 45 PSI is a good number. I have a AFPR and a Mounted FP gage on my car set up to the above numbers.

90camaroirocz

yes I did check it with the regulator unpluged didnt make a difference and I already check the regulator with a vacuum guage and It holds vacuum I got my new pump late last night so I put that in soon also when i give it gas the pressure does not go up it dopes off a little and when you turn the key on you cant even hear the pump run on all my other camaros i could here the pump run for like 5 sec

1991CamaroRslow

iTrader: (3)

The Walbro will bump your fuel pressure up to about where it needs to be with a stock regulator. Change your fuel pump relay while you're in there it's worth the extra cost and time to provide the new pump with clean power.

1993formulav8

Either they work or dont work, no such thing as clean power!!

DJP87Z28

Your right, same thing if he is not getting 36/38 PSI with just the key turned on the Pump is shot.

1991CamaroRslow

iTrader: (3)

No such thing as clean power? Ok then go fray a wire down the line or pull your battery terminal off and just let it touch the corner of the post. That crap might let the lights work but when you go to crank it it's going to shut off. A relay is an electric magnet and inside of it are metal contacts these absolutly do wear out. In any event changing the relay is good insurance when you get a new pump. It's an electrical component and they do go bad in strange ways, it's not a "they work or they don't" thing most of the time. I'm not saying the relay is his problem I'm saying it's something worth changing when you're inevesting in a high flow pump.

firebirdjosh

iTrader: (1)

Technically you're right, but I've NEVER seen a relay show resistance due to age. It's either on or off.

1991CamaroRslow

iTrader: (3)

That's understandable, a relay isn't a valve it's a switch so I can see how clean power may haven't been the best way to word it.

1991CamaroRslow

iTrader: (3)

I had an intermitant problem with my fuel pump relay when I first installed my TPI setup, the pump would work and randomly need alot of cranking to start up I never checked the resistance but the pump didn't act right and the car would stumble from time to time. I changed the fuel pump relay and it made the Walbro pump noticably louder and got rid of the stumble, also didn't have to do the random crank it until the oil pressure was high enough thing.

IROCZZ3

If you want "clean" power going to the pump at all times, run a hotwire kit from Racetronix.

In the turbo Buick world, hotwiring a Walbro pump is one of the first steps to do.

The factory wiring really isn't all that great, and the Racetronix kit is a nice package...plug and play.

midniteplowboyy

iTrader: (1)

I think I would check the FPR first, because at idle or KOEO not much fuel flow would be required and most worn pumps usually would pump more psi. than that, unless you happened to catch it on the way out. Seams like usually when they go out, they go out of a sudden quit pumping or drop to like 10 psi. which vapor locks the fuel rails when the engine is hot. Crimp off your return hose or plug it and check your psi., to make sure its the pump. But odds are it is the pump, but check your voltage so your walbro can live a long happy life, replaced alot of pumps that were knocked out from low voltage, mainly 6.5 chevys where the oil pressure switch cant handle the amperage, just add a relay to them and the repeat fuel pump problem goes away, which kinda sucks since there much easier to change than a third gen. Anyway good luck.

1991CamaroRslow

iTrader: (3)

You can do the hotwire kit yourself with a length of 10 gauge wire ran directly from the battery (or the alternator post) to the plug at the fuel tank, you then wire in an SPDT relay and use the factory hot wire as the turn on lead, make sure to use a high quality BOSCH relay and secure everything as well as possible. Also don't forget the 30 amp fuse at the front of the hot wire (closest to the battery), and reground the pump at the tank with a good ground strap.

firebirdjosh

iTrader: (1)

Oil pressure switch is always nice though- and no present in the hotwire kits. How does it work exactly? I'm debating rewiring mine since I love a good solder and splice every once in a while- but safety first.

b_the_j

i agree with at least replacing the relay, I would not like to replace my $150 pump b/c the relay was stuck on all night long. plus a new battery to boot.

1991CamaroRslow

iTrader: (3)

The hot wire kit works EXACTLY like the stock wiring because your remote (main line turn on) is from the stock wiring. You're just replacing a piece of 16 gauge wire and a circuit with a piece of 10 gauge wire in a direct line (only the Bosch relay in the way). Everything your stock fuel pump system does it will still do.

b_the_j

i dont disagree that wire sucks

midniteplowboyy

iTrader: (1)

thats the way I wire mine, I use the oil pressure switch to trigger the relay and power the relay from a good (fused) source alt., junction block, etc. Output from the relay conected to the original fuel pump wire you cut from the pressure switch. Works great.